The present invention relates to a method and apparatus for manufacturing yarn.
The yarn of the invention may be spun from discontinuous filaments. Thus, with the present invention multifilament strands may be drawn, such multifilament strands being in the form of sliver, roving, or other suitable forms which are well known, and a twisting element similar to a conventional false twister acts on the fibrous strands so as to consolidate them into a yarn having a structure composed, for example, of a core of essentially parallel fibers which are alternately twisted in different directions at different parts of the core with these fibers being held together in twisted condition at certain parts of the core by surface fibers which are uniformly helically wound at the exterior surface of the yarn core.
In conventional ring spinning as well as recently used open-end spinning it is required that the yarn fibers be twisted in the same direction, so that it is necessary with such procedures that one end of the yarn must be continuously rotated during spinning of the yarn. This requirement places an exceedingly great limitation on the linear speed of production inasmuch as for the purpose of introducing typically 10 turns of twist per inch of yarn at a linear operating speed of, for example, 3,000 inches per minute, a rotary speed for this one end of the yarn on the order of 10 times 3,000, or 30,000 revolutions per minute is required. It is, however, well known in the art that ring spinning procedures typically cannot exceed speeds of 20,000 revolutions per minute. Although with open-end spinning machine rotors it is possible to exceed speeds of 50,000 revolutions per minute, the twisting efficiency an open-end spinning machine decreases rapidly with increasing rotary speeds while the power consumed for driving the rotor increases rapidly to uneconomical levels. Therefore, both of these conventional procedures have serious obstacles with respect to improving production speed.
Of course, it is highly desirable to be able to produce yarns according to procedures which do not suffer from these drawbacks. Various procedures have already been proposed and some of them do indeed claim the advantage of significantly higher production speeds, as compared to conventional ring or open-end processes. However, these other types of procedures suffer from other disadvantages ranging from requirements of adhesives to hold the fibers together to undesirably low yarn strengths.